Folic acid and vitamin B 12 supplementation lowers plasma homocysteine but has no effect on serum bone turnover markers in elderly women: a randomized, double-blind, placebo-controlled trial Irena Keser a, ⁎ , Jasminka Z. Ilich b , Nada Vrkić c , Zlatko Giljević d , Irena Colić Barić a a Laboratory for Nutrition Science, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia b Nutrition, Food and Exercise Sciences, Florida State University, FL, USA c Clinical Institute of Chemistry, University Hospital “Sestre milosrdnice,” Zagreb, Croatia d Division of Endocrinology, Department of Internal Medicine, University Hospital Centre, Zagreb, Croatia ARTICLE INFO ABSTRACT Article history: Received 2 July 2012 Revised 5 December 2012 Accepted 2 January 2013 An elevated homocysteine level is a newly recognized risk factor for osteoporosis. Older individuals may have elevated homocysteine levels due to inadequate folate intake and/or lower absorption of vitamin B 12 . The aim of this study was to determine whether there is an impact of folic acid and vitamin B 12 supplementation on homocysteine levels and, subsequently, on bone turnover markers in older women with mildly to moderately elevated homocysteine levels. It is hypothesized that supplementation with folic acid and vitamin B 12 will improve homocysteine levels and, in turn, positively modify bone turnover markers in this population. This randomized, double-blind, placebo-controlled trial included 31 women (65 to 93 years) with homocysteine levels greater than 10 μmol/L. Participants were randomly assigned to receive either a daily folic acid (800 μg) and vitamin B 12 (1000 μg) (n = 17) or a matching placebo (n = 14) for 4 months. The results showed significantly lower homocysteine concentrations in the vitamin group compared to the placebo group (10.6 vs 18.5 μmol/L, P = .007). No significant difference in serum alkaline phosphatase or C-terminal cross-linking telopeptide of type I collagen was found between the vitamin and placebo groups before or after supplementation. The use of folic acid and vitamin B 12 as a dietary supplement to improve homocysteine levels could be beneficial for older women, but additional research must be conducted in a larger population and for a longer period to determine if there is an impact of supplementation on bone turnover markers or other indicators of bone health. © 2013 Elsevier Inc. All rights reserved. Keywords: Homocysteine Bone turnover markers Folic acid Vitamin B 12 Older women NUTRITION RESEARCH 33 (2013) 211 – 219 Abbreviations: ALP, alkaline phosphatase; CTX, C-terminal cross-linking telopeptide of type I collagen; DPD, deoxypyridinoline; RBC, red blood cells. ⁎ Corresponding author. Laboratory for Nutrition Science, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10 000 Zagreb, Croatia. Tel.: +385 1 46 05 049. E-mail address: ikeser@pbf.hr (I. Keser). 0271-5317/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.nutres.2013.01.002 Available online at www.sciencedirect.com www.nrjournal.com